Severe Wi-Fi interference within a corporate headquarters causing devices to constantly drop off the network is most likely due to too much wireless reflection. Wireless reflection occurs when Wi-Fi signals bounce off surfaces like walls, metal, or glass, causing multipath interference. This can lead to poor signal quality and frequent disconnections. Other causes like wireless absorption, too many repeaters, or too many client connections can also affect Wi-Fi performance, but excessive reflection is a common culprit in environments with many reflective surfaces.
Reference: CompTIA Network+ Certification Exam Objectives - Wireless Networks section.